Genetic information is stored in DNA, passes through RNA, and is expressed as protein. The RNA is more than a passive intermediary in this over-simplified scheme. The primary transcript of the gene, a base-for-base copy of the DNA coding strand, in the majority of cases is modified before playing its biological role. These post transcriptional modifications are widespread, being found in procaryotic and eucaryotic cells and in all major classes of RNA (such as ribosomal, messenger, transfer and other RNAs). These alterations are of several kinds: individual nucleotides may be modified by methylation, reduction, or addition of complex groups; sequences may be added to or removed from either, or addition of complex groups; sequences may be added to or removed from either, or both of the RNA termini; and internal sequences may be excised form within RNA molecules and the remaining flanking parts religated together. This latter type of processing, "splicing", has not been observed in procaryotes. The biological importance of RNA processing is very great since it has major impact on the stabilization of RNA, alteration of RNA function, control of gene expression, and activation of precursors. This field is a dynamic and rapidly developing area of research. The objective of the RNA Processing Meeting is to bring together the increasing number of people who are working in the fast-expanding field, so that they may exchange recent data and techniques and critically evaluate the status and progress of research in this area. No comparable forum for such a gathering exists and the field should benefit greatly from the planned meeting. Following an initial productive and successful conference in 1982, this application requests funds for the second and third of three such consecutive annual meetings.